The document DE 196 35 582 C1 discloses such a power semiconductor component with a bridge circuit having at least one high-side switch (HSS) and at least one low-side switch (LSS), which component has a first base power semiconductor chip containing a vertical first transistor. A further second power semiconductor chip having a second vertical transistor is mounted on the first base power semiconductor chip so that the conduction paths of the two transistors are connected in series. An arrangement of this type is shown by FIGS. 3 and 4.
FIG. 3 shows a conventional bridge circuit 10 of power semiconductor chips 1 and 2, the base power semiconductor chip 1 being mounted on a heat sink 6 and having a high-side switch HSS. The drain connection 7 of the high-side switch HSS forms the rear side of the base power semiconductor chip 1, which is mounted on the heat sink 6. A further power semiconductor chip 2 is stacked as a low-side switch LSS on the source area at the top side of the base power semiconductor chip 1.
For this purpose, the drain region of the low-side switch LSS is mounted on the source region of the high-side switch HSS and forms the node 4, which can be connected via the external connection 3. The source region of the low-side switch LSS can likewise be contact-connected via the external connection 5 by bonding. The external connections 8 and 9 serve for driving the respective switches HSS and LSS of the bridge circuit.
One realization of the bridge circuit 10 is shown in FIG. 4, in the case of which the bridge circuit 10 is arranged in a housing 11 with external leads as external connections 3 and 5. In this case, the source area SH of the high-side switch HSS situated at the surface of the base power semiconductor chip 1 is larger than the power semiconductor chip 2 stacked on it. As a result, the contact-connection can be effected via the contact area at the node 4 in a simple manner by means of bonding wire 12 to the external lead connection 3. The source area SL of the semiconductor chip 2 is also connected to the other external lead contact 5 from above likewise by means of a bonding wire 13.
What is disadvantageous in the case of this bridge circuit 10 is that the drain connection basic area of the low-side switch LSS, which is realized as a stacked power semiconductor chip 2, is smaller than the source contact area of the high-side switch HSS in the base power semiconductor chip 1. This is associated with the disadvantage that the permissible current consumption of the bridge circuit branch 10 is significantly restricted by the reduced size of the stacked power semiconductor component 2.
Such a bridge circuit with a high-side switch as base chip is disadvantageous especially as, in a bridge circuit of this type, the larger current flow is to be switched through the low-side switch and it is not possible to effect problem-free linking to a thermal sink with a corresponding heat sink for dissipating the heat loss in the known circuit construction.